This invention relates to an optical fiber termination, especially for use in a demountable optical fiber connector, and a method of making such a termination.
In an optical fiber connector, accurate alignment of the fibers to be connected is essential to avoid excessive losses of light. Thus the slightest inaccuracy in this alignment leads, due to the small cross-section of the fibers used to convey the light, to a considerable loss of light. To overcome, or at least to reduce, this difficulty it is known to fix the end of an optical fiber with respect to a lens which, although physically small, is large in diameter compared with the fiber diameter. This lens produces a collimated expanded beam of light whose diameter may be of the order of 0.5 mm--which also is large compared with the diameter of the optical fiber. The beam from one such lens is so aimed as to fall on the lens of the other termination, so that when two such terminations are used to connect the fibers, the radial tolerance due to misalignment of the lens is considerably less tight than the radial tolerance between two fibers which mate directly.
The fiber in such a termination has to be radially and angularly aligned with respect to the lens during manufacture, but the terminations are aligned by the casing in which they are placed. In the case of this latter alignment, radial tolerance is relaxed at the expense of a tightening in the corresponding angular tolerance, so a balance has to be struck. Such terminations in addition to their performance being relatively insensitive to radial misalignment, are not as susceptible to damage by abrasion or to troubles due to the presence of dust.
The object of the present invention is to provide an improved optical fiber termination of the type referred to above, and to provide a method of making such a termination.